EVALUATION OF SMALL-BOWEL MOTILITY

Disturbances of small bowel motor function are increasingly recognized in clinical practice, either in the setting of an underlying disease that may affect the neuro-hormonal control of gut motility, such as diabetes or scleroderma, or as part of unexplained intestinal dysfunctions such as the irritable bowel syndrome or chronic idiopathic intestinal pseudo-obstruction. In the absence of endoscopic or radiological mucosal disease, it is often clinically helpful to define the motor function of the small bowel to understand the origin of the patient's symptoms. The hydrogen breath test after a lactulose oral load is currently used to measure mouth to caecum transit time. However, the reproducibility of this test is poor, and the range of normal values is wide. Scintigraphic determination of small intestinal transit time overcomes some of the limitations of the hydrogen breath test. This is however a time consuming procedure - up to 10 hrs when the time for aquisition, processing and analysis is included - and the costs prohibit widespread application of the technique. It is further restricted by the exposure to ionising radiation, particularly if repeated evaluations are necessary, for example in drugs trials. Manometry records mechanical activity of the bowel and detects quantitative and qualitative changes of small intestinal motility. As with scintigraphy, high costs and radiation exposure limit its usefulness. The major clinical application of the technique is in the diagnosis of chronic intestinal pseudo-obstruction.